Android or iOS? Well, the jury is still out on that. But, there is one definite area where iOS still has an edge i.e. the butter smooth user experience. How? Even Apple's latest flagship, iPhone 6 Plus comes packed with a gig of RAM which is apparently enough to give the users a smooth experience. In stark contrast, Google’s flagship- the Nexus 6 - has a massive 3 GB RAM but still falls short for its heavy OS and slows down after sometime.
The reason is quite simple. It's all about the code. Android is coded in java and hence employs a garbage collection solution for ‘effective’ memory management. This technique needs a lot of space and depending upon the version it may sometimes even require around 4 to 8 times the memory needed for an actual good performance of the system and more prolonged run-time of a background process will result in great heap of GC and of course, a laggy experience over time until the memory gets constrained.

Garbage collector of JAVA

On the other hand, iOS doesn't use this sort of memory management technique and hence even a 1 GB device looks amazingly smoother than a high-end 3 GB android after prolonged use.
Now, before we heat things up, we do agree that more RAM has its perks. The reduced content refreshes in browser and games are a breather at times but nothing beats iOS when it comes to the polished nature of the OS.